#include<iostream>
#include<vector>
#include<queue>
#include<cstring>
#include<cmath>
#include<map>
#include<set>
#include<cstdio>
#include<algorithm>
#define debug(a) cout<<#a<<"="<<a<<endl;
using namespace std;
const int maxn=2e5+1000;
typedef long long LL;
inline LL read(){LL x=0,f=1;char ch=getchar();	while (!isdigit(ch)){if (ch=='-') f=-1;ch=getchar();}while (isdigit(ch)){x=x*10+ch-48;ch=getchar();}
return x*f;}
char str[maxn];
int main(void){
   cin.tie(0);std::ios::sync_with_stdio(false);
   ////LL n,k;cin>>n>>k;
   cin>>(str+1);
   LL n=strlen(str+1);
   LL sum=0;
   for(LL i=1;i<=n;i++){
      for(LL j=i+1;j<n;j++){
         if(str[i]==str[j]&&str[i+1]==str[j+1]){
            cout<<"i="<<i<<" "<<"j="<<j<<"\n";
            sum++;
         }
      }
   }
   cout<<sum<<"\n";
   return 0;
}
